Long epoxy cure time (D4), question about temp/speed up

matt_unique · Post by **matt_unique** » Sat Feb 07, 2004 10:56 pm

I received the small boat kit with the medium hardener. I am building this D4 in the basement of a friends house. I was careful to mix the resin/hardener 2:1 and stir it up thoroughly but after 6 hours it was still sticky to the touch. I'm not sure what the temp is in the basement, I estimate between 50 - 60 degrees F.

I know this is on the cold side for medium hardener but I assume it will eventually harden? This is my second D4 but the first time I am using the System Three materials. Previously I used the West System from West Marine. I think the temps for boat number 1 were similar but the resin cured much faster. Next time around I would go with the fast hardener.

I am concerned about doing filets if it takes forever to cure the resin. Should I invest in a cheap hair dryer to help speed up the cure time?

Thanks

--Matt

JamesSloan · Post by **JamesSloan** » Sat Feb 07, 2004 11:22 pm

A few hours (10-12 or more) isn't unusual in that sort of temperature. Check it in 24 hours or so and you should see a difference. A hair dryer/heat gun isn't really effective because the heat is so localized. If it still isn't nice & hard after a couple of days, get some heat lamps on it and see if that does the trick.

Don't worry about the fillets. The cure time is longer the more the epoxy is spread out. A fillet is more stuff in less space and permits the chemical process to complete quicker. I know it sounds backwards, but that's the way it works out.

Good Luck!!

danmcmartin · Post by **danmcmartin** » Sun Feb 08, 2004 2:38 pm

I had similar experiences with the medium hardener in cooler temps. I went to the fast hardener and it still took hours (up to 24 in very low temps). Just be patient or get some heat in the basement. Don't worry, sometimes I couldn't sand until the next weekend becuase it was slightly soft after 36 hours. Patience is a virtue.

DrBones · Post by **DrBones** » Sun Feb 08, 2004 5:40 pm

Jacques has recommended to use a light bulb and put it under the boat (if it's flipped and let it 'heat' up the area. Another tip is to warm up the resin/hardener while you mix it and then apply it.

matt_unique · Post by **matt_unique** » Sun Feb 08, 2004 10:14 pm

Edward · Post by **Edward** » Sun Feb 08, 2004 10:24 pm

As others have said Matt just be patient. You can warm the epoxy and hardner if you want. Last year I was working outside in 40 degree temps and I kept the epoxy in a cooler half filled with very hot water. It sped things up a bit...not alot but some. Also remember for the filleting it's good to have a slower cure; that way you can get he glass tape over it while it's still plaible.

deedee · Post by **deedee** » Mon Feb 09, 2004 1:40 am

i am working outside here in va. beach and on most of the days lately it has been below freezing . i just keep the epoxy inside , mix indoors and keep it inside until i'm ready to apply it. you can also use an electric blanket over your work site before and after you apply the resin to bring the temp. up alittle. the only bad thing about working in the cold with the epoxy is that it will be more like working with 80-90 weight instead of 30 weight. being cold it does not penetrate the material as well . you can use a heat gun to warm up the wood. i just keep working it into the wood and also into the biax for quite a while if it is really cold because of it not penetrating as well . i fell out of my chair when i saw my electric bill this month . i think it was because of all the heating products i am using on the darn boat. gotta do what you have to do .

Troutlet · Post by **Troutlet** » Mon Feb 09, 2004 6:02 am

I'm in Southern Virginia, yesterday's high was 40 degrees. I have my project in a 'tarp tent'. Within the tent I laid clear plastic sheeting over the entire project and propped it up with scrap pieces of wood. I then placed two 250 watt heating bulbs under the sheeting and a propane tent heater underneath the set up. Everything was secured in place and I babysat it for a couple hours before I was confident that there would not be a fire.
I was able to sustain 70 degrees under my tent within a tent.

Post by **jacquesmm** » Mon Feb 09, 2004 9:09 am

At 50 to 60 degrees, it takes several days to reach a full cure. It's normal.

matt_unique · Post by **matt_unique** » Mon Feb 09, 2004 9:48 am

jacquesmm wrote:At 50 to 60 degrees, it takes several days to reach a full cure. It's normal.

I will soon begin the filet's. Should I mix it all up in warm temps so the filet's cure sooner? Should I be concerned about the filet's sagging once the tape and epoxy is all applied at those 50-60 degree temps?

Thanks

--Matt

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